This invention is directed to a fluid absorbent article generally, and specifically to a fluid absorbent article which is particularly suitable for use in surgical applications.
Absorbent or absorptive structures are generally known and are utilized in various different articles of commerce. For example, some well known articles which utilize fluid absorbent components include disposable diapers, sanitary napkins, tampons, bed pads, surgical coverings, incontinence pads, towels, bandages, etc. Generally, such articles are single-use, disposable articles and have replaced permanent absorbent articles, which are designed to be laundered and re-used.
Depending upon the use of such articles, they will have various different constructions, although the articles often utilize common components having somewhat similar functions. Generally, such articles are meant to absorb fluids, such as bodily fluids, and retain those fluids within the article so that they may be cleanly disposed. The functions and qualities of the absorbent articles minimize mess and enhance clean-up and disposal of the bodily fluids. While the articles have similar absorbent qualities in common, their overall construction and components will generally be tailored to the specific use of the article.
In particular, medical articles or products, and especially those utilized in the surgical arena, such as surgical covers and drapes, must be able to absorb large amounts of fluids somewhat rapidly. Furthermore, they must be able to do so when draped over an object, thereby presenting a significantly sloped surface. Surgical drapes are most frequently draped over the patient proximate to the area where a surgical procedure is to take place. The absorbent media or components must provide rapid absorption of fluids associated with the surgical procedure, such as blood. Furthermore, the absorbent media also must have a relatively high fluid capacity and good integrity so that it does not degrade or fall apart during use.
In their basic design, surgical drapes have been simply a sheet of absorbent material. For conventional surgical drapes, the most commonly acceptable absorbent media is referred to as a cellulosic airlaid. Cellulosic airlaids are made of a plurality of loose cellulose fibers which are bonded together. One drawback of cellulosic airlaids is that the loose fibers may actually come loose during use of the surgical drape, and may thereby enter the wound. While the body may break down cellulose and dispose of it without intervention, it is still an undesirable feature. One approach to reducing the possibility of loose fibers is to simply bond the fibers more tightly. However, this results in lowering both the absorption rate of the media and also the absorption capacity. An additional approach, particularly for high-end or more expensive drapes, has been to utilize a netting component on a surface of the fibrous cellulose component to contain any fibers while maintaining a suitable absorption rate and capacity. Again, however, the netting and bonding media to attach it may also reduce the absorption rate.
Another possible solution for fibrous absorbent media proposed by the inventors, is to utilize a layer component having a series of apertures formed therein. Such a layer component is often referred to as an apertured film. While apertured films have desirable characteristics, they have also presented difficulties as well. Generally, apertured films utilize rows or lines of apertures which may provide rapid liquid flow therethrough when the film and any absorbent material are placed on a flat surface or are incorporated into a formed or shaped garment which acts to physically capture and contain the liquid. However, if the film is inclined and the fluid is rapidly applied, as is often the case when a surgical drape is positioned over a patient, most apertured films do not provide the desirable fluid flow therethrough for absorption by the absorbent media underneath. Existing apertured film designs do not present significant hindrance to the flow of fluid over the surface of the film. As a result, the fluid rolls over the surface and drips from the drape. This is certainly undesirable for an absorbent article. Consequently, certain apertured films have proven useful for generally flat applications or for use in formed or shaped garments, but have proven undesirable for a surgical drape or other surgical application.
Another issue with apertured films, which is also an issue with netting, is that the desired surface openness which allows fluid to flow through the film, also allows any bonding material or adhesive underneath the film to flow onto or be exposed to the surface of the film. Bonding material is positioned between the film and an absorbent layer underneath. For certain absorbent articles, such as diapers or feminine hygiene products, this openness is generally not a problem. Diapers and feminine hygiene products are usually formed to be used without modification, such as openings cut therein, and the bonding materials between the multiple layers may be marginally or peripherally positioned, keeping it out of the primary absorbent areas of the article. However, with surgical drapes, the apertured film should generally be bonded across the whole area of the absorbent media in order to maintain the bond everywhere when the drape is altered. For example, during surgery, one or more holes will be cut in the drape to allow access to the surgery site. The layers should not come apart at the hole and, therefore, the layers must be bonded together generally all over the drape.
Bonding over the entire area of the absorbent article has provided some challenges which are unresolved by the prior art. First, enough bonding material must be utilized to hold the apertured film to the absorbent media. However, such significant bonding may sometimes block the apertures and reduce the flow rate through the apertured film. Furthermore, the bonding media may detrimentally affect the distribution rate over the absorbent media. Still further, the fluid holding capacity of the absorbent media may be compromised.
Another issue which must be addressed by a surgical drape article is exposure of the surgical personnel, the patient, and surgery opening to the tacky bonding media. The openness of apertured films lends itself to a bleed-through of the bonding media or adhesive and subsequent exposure of the patient""s skin to the tackiness of the bonding media. Furthermore, the tacky drape may be difficult to manipulate and position. This aspect should be minimized in a surgical drape, which will have bonding media throughout, rather than in marginal areas which might not significantly contact the skin.
Prior art surgical structures, particularly those using cellulose as an absorbent media, also have a tendency to swell in size upon the absorption of fluids. In the past, such swelling has broken the surface bond of the bonding media causing separation of the various layers of the drape when the drape absorbs fluid. Improving the bond by using a greater quantity of the bonding agent or adhesive is unacceptable because it causes a reduction of the fluid absorbency rate and reduces the overall fluid capacity of the article.
Accordingly, it is an objective of the invention to improve upon existing absorbent articles and particularly to provide an improved article for surgical applications.
It is another objective of the invention to improve the absorbent characteristics of a surgical article, such as a surgical drape, by reducing fluid flow off of the article, improving the distribution of fluid flow over the article and improving the fluid capacity of the article.
It is still a further objective to utilize an absorbent article having an apertured layer, wherein the integrity of the apertured layer is maintained to provide improved absorbent characteristics.
It is another objective to reduce tacky adhesives or bonding media which bleeds through the apertures of the apertured film while maintaining a sufficient bond between the layers, both when the absorbent media is wet and when it is dry.
These objectives and other objectives will become more readily apparent from the description of the invention hereinbelow.
The present invention is a unique combination of elements which provides a fluid absorbent article which is particularly suitable for surgical applications, such as for a surgical drape. The article is operable for absorbing a large amount of fluid, such as during a bloody surgical procedure, even when it is oriented at a significant slope with respect to a ground surface. The combination of elements operates to absorb and hold the fluid at a rapid rate, and may be positioned and modified, such as by cutting a hole therein, without compromising its absorbent qualities. To that end, the fluid absorbent article directed to surgical applications comprises a top layer, including an apertured film having a plurality of apertures formed therein. The apertures have bases and apices, wherein the base of each aperture is located in an upper surface of the top layer, and the apex is positioned at a depth below the base and the upper surface of the top layer. An absorbent layer, including an absorbent media, is positioned to underlie the top layer and to be generally coextensive therewith. The absorbent layer absorbs fluid passing through the top layer and disperses and contains those fluids.
In accordance with one aspect of the present invention, the bases of the apertures have a plurality of generally straight sides. In one embodiment, the aperture bases are pentagonal or hexagonal in shape. The apertures of the bases are positioned relative to the upper surface to present a plurality of different angles to fluid flowing over the upper surface. The different angles presented by the straight sides of the aperture bases hinder and divert the fluid so that it more readily passes through the apertures to the absorbent layer.
In accordance with another aspect of the present invention, a bonding layer, including a bonding media, is positioned between the top layer and absorbent layer. The bonding layer is operable for bonding the apices of the apertures to the absorbent media, generally over the length and width of those layers. In that way, the bonding layer secures the layers together, generally over the length and width of the fluid absorbent article. Since the bonding layer generally bonds only at the apices, the depth of the apertures and the thickness three-dimensional top layer are maintained. In one embodiment, the bonding media is applied between the layers in a plurality of strands. The strands generally have a width dimension which is less than the depth of the apertures in order to bond the top layer primarily at the apices of the apertures. Furthermore, the width dimension of the strands is also less than the average width dimension of the aperture apices, so that the bonding layer does not significantly interfere with the flow of fluid through the top layer. The bonding layer may be applied in a plurality of spiral strands having a diameter in the range of 1-12 inches, and preferably 3-4 inches.
In accordance with another aspect of the present invention, the bonding media has a tack after curing which is significantly reduced from its tack prior to curing. In that way, a suitable bond is created between the top layer and absorbent layer during formation of the fluid absorbent article. However, after curing, the tack of the bonding media is reduced over 60%, preferably over 70-75% from its tack prior to curing. The top layer may have an open area defined by the apertures in the upper surface of the layer in the range of approximately 15-35%. As such, the apertures expose the bonding media below. Because of the small dimensions of the strands, as well as the reduction in tack after curing, the finished fluid absorbent article does not have an undesirable tackiness. Simultaneously, the bonding layer still maintains a bond strength of at least 20 grams/inch, whether the fluid article is dry or wet from having absorbed fluid. The maintained bond strength, even when wet, is particularly desirable for a surgical drape, as the layers of the drape are bonded together over generally the entire area of the drape, rather than just marginal surfaces. As such, the bonding media, in some area of the drape, will always be exposed to fluid, and still must maintain strength to prevent separation of the layers at the absorbent area.
Therefore, the unique fluid absorbent article of the invention utilizes the combination of elements and properties which provides a desirable article, such as for surgical applications, and addresses the objectives set forth above and other objectives. The details of the invention and its particular advantages will be more readily understood from the Detailed Description of the Invention set forth hereinbelow.